Hayes Syncronizer Trailer Brake Controller - 1 to 2 Axles - Time Delayed
Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug

Part Numbers: HA81725,HA81794-HBC

Our Price: $85.69
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HA81725 - Under-Dash Box Hayes Time Delayed Controller
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Hayes Syncronizer Trailer Brake Controller - 1 to 2 Axles - Time Delayed
part number: HA81725

Economically priced brake controller automatically engages your trailer's brakes with a preset intensity when you apply the brakes in your vehicle. Power output is easily adjustable. Includes LED indicator and manual override.


  • Brake controller activates trailer brakes with preset intensity
    • Signal is sent to trailer brakes when tow vehicle's brakes are activated
  • Adjustable power output lets you determine the amount of power sent to the trailer's brakes
    • Set to higher output when towing in hilly terrain or with a fully loaded trailer
    • Back off power output when towing a lightweight or empty trailer
  • Red LED indicator on front of unit illuminates when trailer's brakes are applied
    • Light glows brighter as power output increases
  • Built-in safeguards protect your vehicle and your trailer
    • Manual override illuminates brake lights on tow vehicle and trailer
    • Current limiter protects vehicle from shorts in the trailer wiring
    • Hazard flasher immunity prevents pulsing of the brakes when flashers are activated
  • Slide-bar manual override
  • Dependable solid-state construction
  • Quick and easy installation
    • Can be mounted at any angle in any plane, and in any direction
    • Mounting bracket and hardware included
    • Plug-in, vehicle-specific brake control adapter (sold separately) can be used for certain applications to reduce installation time
  • Made in the USA


  • Application: trailers with up to 2 axles (4 brake assemblies)
    • Designed for use with electric brakes only
  • Dimensions: 5-1/4" long x 3-1/8" wide x 1-1/4" tall
  • 3-Year limited warranty

Time-Delayed Braking

The Syncronizer applies your trailer's brakes when the brake pedal in your tow vehicle is engaged. Every time you apply the brakes in your vehicle, a signal is sent - via the brake switch - to the Syncronizer. The controller then sends power out to your trailer brakes to activate them with an intensity you have set. The amount of braking power can be adjusted to suit your preference. To determine the amount of power that is best for your application, you must test out your towing setup and choose what feels best.

A time-delay controller is so named because there is a delay between the time that you initially apply the brakes in your tow vehicle and the time that the controller reaches the set maximum power output. Unlike a proportional brake controller, which activates your trailer's brakes based on the deceleration of your tow vehicle, the Syncronizer sends power out in the same way, with the same user-set delay, no matter the braking situation. The controller will continue to send out power to the trailer brakes as long as your foot is on the brake pedal, even when your truck and trailer have come to a stop.

Built-In Controls on the Syncronizer

Syncronizer Controls

The diagram above shows the controls and components of the Hayes Syncronizer electric trailer brake controller.

Power Output Control

The power output control lets you set the maximum amount of power that will be applied to your trailer's brakes. Typically, the power output is only readjusted if you switch from a heavy, loaded trailer to a much lighter, empty trailer - or vice versa.

During the initial setup process, use the thumbwheel on the left front of the Syncronizer to adjust the output. To get more power to your brakes, rotate the dial upward. To decrease the power output, move it downward.

Red Indicator Light

The red LED indicator light illuminates when the trailer brakes are applied. This light glows brighter as the power output to the trailer brakes increases.

Slide-Bar Manual Override

The manual slide lever overrides the preset power output and allows the operator to engage the trailer brakes without using the vehicle's brakes. In addition to being a necessary safety feature, this option helps to control trailer sway by slowing the trailer to put it back solidly behind the tow vehicle.

You can also engage the manual override to help you move a sliding 5th-wheel hitch closer to your truck's tailgate for tight maneuvering during slow speed turns. Just apply the manual override to hold the trailer in place while slowly moving the tow vehicle forward.

Quick, Simple Installation

Because inertia plays no role in the functioning of this controller, you do not have to mount the unit at any particular angle or position it in any particular direction. As a result, mounting options are limitless, so long as you can still easily access the manual override.

Installation of the Syncronizer requires that you either purchase a custom wiring adapter designed to plug into the controller or that you hardwire the controller directly into your vehicle. To hardwire the unit, you must remove the plug at the end of the integrated wiring harness.

Installation Accessories

The Hayes vehicle-specific, dual-mated wiring adapter is available for most newer trucks and SUVs with tow packages. One end of the custom adapter plugs into your vehicle's brake controller port, and the other end plugs into the controller - no hardwiring required.

Hayes also offers a universal wiring harness (HA81789-HBC - sold separately) that plugs into any Hayes brake controller. The 4 leads on the universal harness can then be hardwired into your vehicle. By splicing the universal adapter into your wiring instead of directly connecting the brake controller to your wiring, you gain the ability to unplug and remove the controller from your vehicle should the need arise.


  • If a custom brake-control wiring adapter is not available for your vehicle, one of the following will be required:
    • 20-Amp circuit breaker (9506P - sold separately) for 2-brake applications
    • 30-Amp circuit breaker (38630 - sold separately) for 4-brake applications
  • If you're hardwiring the controller, it is also suggested that you install an in-line fuse between the controller and the stop light switch (required on 1999 and newer Fords).

See also etrailer.com's exclusive 7- and 4-way brake control installation kit (ETBC7 - sold separately) if you don't already have a 7-way plug at the back of your vehicle.

81725 Hayes Synchronizer Electric Brake Controller - Time Based

Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug
part number: HA81794-HBC

Install your Hayes electric trailer brake controller quickly and easily with this custom wiring adapter. One end plugs into the controller, and the other plugs into the built-in port behind your vehicle's dash.


  • Plug-in wiring adapter allows for quick, simple installation of your electric trailer brake controller
  • No cutting or splicing required
    • Custom connector end plugs into the built-in port behind the dash of your vehicle
    • Opposite end plugs into the back of your electric brake controller
  • Compatible with time-delayed and proportional brake controllers from Hayes
  • Made in the USA

Installation of Hayes Brake Controller Adapter

To install your Hayes electric brake controller, you need to connect the wiring of the controller to your vehicle. Certain auto manufacturers offer pre-wired options, typically known as tow packages, in which the wiring is run for you from the dash to the trailer connector on the back of your vehicle. Usually when this is done, a port is installed at your dash so that you can easily plug in a brake controller.

This adapter plugs into the built-in connector behind your vehicle's dashboard. To access this connector, first locate the instrument cluster finish panel in the center of the dash, near the driver's side. Carefully pry the panel out and undo the locking tabs to remove the panel. Plug the adapter into the mating connector in the large gray housing behind the panel.

No hardwiring is required to install this adapter. After you plug it into the factory port, you simply plug the other end of the adapter directly into your electric trailer brake controller. Because there are no wires to connect, installation is not permanent. You can unplug and remove your brake controller at any time to transfer it to another vehicle or securely stow it away.

81794HBC Hayes Dual-Mated Brake Control Wiring Harness - Ford

Replaces 81794-HBC

Customer Reviews

Hayes Syncronizer Trailer Brake Controller - 1 to 2 Axles - Time Delayed - HA81725

Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug - HA81794-HBC

Average Customer Rating:  4.9 out of 5 stars   (27 Customer Reviews)

Economically priced brake controller automatically engages your trailer's brakes with a preset intensity when you apply the brakes in your vehicle. Power output is easily adjustable. Includes LED indicator and manual override. Install your Hayes electric trailer brake controller quickly and easily with this custom wiring adapter. One end plugs into the controller, and the other plugs into the built-in port behind your vehicle's dash.

- HA81725
by: Cindy B03/12/2017

Ty for following up with your product that we purchased si far so good * 351738

- HA81725
by: Bob P.04/10/2016

Original supplied item was defective, however Hayes customer service immediately sent another unit and it works great. With the addition of a small removable slip in bracket for the console of my 2012 GMC 1500 Crew Cab and the wiring adapter, I can simply plug and play when I need the controller as opposed to a permanent installation that I have in my other pickup. 243611

- HA81794-HBC
by: Ron12/28/2019
2019 Ford F-150

Etrailer was very helpful with all the info needed to buy the correct connecting cable for my Hayes brake control. Delivery was quicker than expected & of course the cable works as stated. Great job again! Thanks Etrailer! 734677

- HA81725
by: Fernando12/11/2019

Works well. At an affordable price. 730671

- HA81725
by: Frank11/16/2019

easy to install. Brakes tested good to trailer. I used self taping screws to mount brackets, rather than the bolts and nuts that it came with.It was to difficult to get my hands in position to use bolts and nuts (no big deal). 726182

- HA81725
by: Wally08/19/2019

very good. 691467

- HA81725
by: George08/11/2019

Worked fine, plug and play with adapter cord. 683496

- HA81725
by: Kevin06/18/2019

The web site was easy to use. the parts arrived quickly and was a great experience. 659586

- HA81725
by: Duncan06/10/2019

super fast delviery great product pluged right in 655869

Best controller out there
Duncan - 06/10/2020


- HA81725
by: Dave 2018 ram 1500 eco04/07/2019

Installed in 10mins in 2018 ram 1500 ecodiesel, have not used with trailer yet. Seems good for price, mounting bracket could be made a little better. Good service from e trailer 619266

- HA81725
by: William03/06/2019

Great product great company. 610534

Sold that truck but the product was A+ easy install worked perfectly.
William - 03/07/2020


- HA81725
by: Charles07/13/2018

Fast delivery, excellent product at a fair price. Thanks 541402

- HA81794-HBC
by: John06/29/2018

This harnress was exactly what I ordered. Very pleased as usual. I have to add that for a while I was sure that I had received the wrong product. Then I watched an Etrailer install video and realized that the plug in my truck had an adapter attached that had to be removed before the harness could be plugged in. 5 minutes later I was done and ready to tow. 528384

- HA81725
by: Lydia12/12/2017

This worked well, thanks. 459539

- HA81725
by: Jesus12/12/2017

Very good 459450

- HA81794-HBC
by: Budman08/15/2017

I, order wrong wire adapter by mistake, I called etrailer, and spoke to nice lady there and gave the number of the one I had ordered, she looked up what I needed and placed order while I was on the phone with her. Got the adapter and it was the correct one and works perfect. To help others Ford puts a hard shell in there wire to protect against short circuit, it has to be removed before you can plug any adapters into it. 420629

- HA81725
by: Jay04/14/2017

Works as it should! No issues. 367432

- HA81725
by: Andrew Ammerman04/11/2017

The trailer seems to be holding up just fine. It was a good investment for my small business and I'm thinking about buying another from you. 367445

- HA81725
by: Jamie r03/27/2017

Ive used this controlrr a couple of tumes and really like it i got great service and fast delivery thank you so much 359239

- HA81725
by: darryl01/13/2017

They told me it would be a week for delivery since it was coming by mail, I got it in three days. Very fast and easy to order. 335002

- HA81725
by: Greg12/05/2016

Good product works great. 322355

- HA81725
by: Wayne11/18/2016

My Hayes Brake controller was as described, Easily wired,mounted reasonably price, 317660

- HA81725
by: Rob08/27/2016

Installed in 10 minutes. Works excellent and combined with the wiring adapter was a simple plug and play. 288285

- HA81725
by: Brad03/03/2016

Product and function is working fine. 239354

- HA81725
by: Charles H05/30/2015

Well pleased with the break box and wiring hook up, Very simple to install. 198756

Show More Reviews

Ask the Experts about this Trailer Brake Controller

  • Brake Controller Compatibility with 2015 Audi Q7 TDI Prestige
  • The Hayes Syncronizer Trailer Brake Controller -Time Delayed # HA81725 can be used on your 2015 Audi Q7. You will need to hardwire your controller, but I recommend using the wiring adapter # HA81789-HBC to allow you the quick connection so you can use this controller on other vehicles if desired. You will also need to use additional wiring as you pointed out. You will need to ask your authorized dealer for #1J0-972-782 housing (qty. 1) and #000-979-228 wire/terminal assemblies (qty.
    view full answer...

  • Parts Needed to Install Brake Controller in a 2016 Ford Transit
  • To install a brake controller in your 2016 Ford Transit Connect tou will need to start with a 4-way (if you do not have one). For that you would want the # C56218. From there you would need to convert the 4-way to a 7-way so that you can install the brake controller. For that you will want the Brake Controller Install Kit and 7-Way Adapter part # ETBC7. I attached installation instructions and an install video for this product as well. For a brake controller I would recommend the
    view full answer...

  • Custom Wiring Harness for Hayes Brake Controller in 2017 GMC Sierra 1500
  • Your Hayes Syncronizer Trailer Brake Controller - 1 to 2 Axles - Time Delayed # HA81725 is confirmed to fit your 2017 GMC Sierra 1500 using the custom wiring harness # HA81798-HBC. This adapter plugs into the port that is built into the electric junction box underneath your vehicle's dash. The black box is located to the left of the steering column, just above the carpet. To plug in the adapter, first remove the cover on the box. The adapter plugs into the first slot on the left, in the
    view full answer...

  • How to Complete Hardwire Installation of Hayes Synchronizer Brake Controller
  • I'd be happy to assist with that. In addition to the # HA81725 Hayes Synchroinizer brake controller, you'll need a universal wiring harness, part # HA81789-HBC and our Brake Controller Installation Kit, part # ETBC7. The kit includes everything necessary to install a brake controller in your vehicle, with the exception of the controller itself and a 4-pole trailer wiring harness for the vehicle. If you click the provided link, you can see some FAQ articles about installing a brake
    view full answer...

  • Will Hayes Syncronizer Brake Controller Work on a 2016 Ram 1500
  • In the newer Rams the stoplight switch of yhe truck uses a lower voltage signal than most vehicles so only some controllers can be used. The confusion you have experienced with your local dealer and trailer shop is most likely stemming from that. We have confirmation from Hayes that their Syncronizer part # HA81725 will work on your 2016 Ram 1500 and all you would need to install it is the harness part # HA81795-HBC.
    view full answer...

  • Wiring Adapter to Install Hayes Synchronizer # HA81725 Brake Controller in 2008 Toyota Tacoma
  • Hayes does indeed offer a brake controller wiring adapter that's compatible with the 2008 Toyota Tacoma that's equipped with the factory 7-way trailer connector, part # HA81785-HBC. I've provided you a photo of what the connector that will plug in under the dash looks like. It's a four pin connector, and you can clearly see the pin-out in the photo I've edited for you. Your factory connector under the dash will have 5 pins, but the aftermarket wiring adapters and brake controllers
    view full answer...

  • Troubleshooting Hayes Syncronizer Trailer Brake Controller
  • That is not normal. The Hayes Syncronizer Trailer Brake Controller - 1 to 2 Axles - Time Delayed # HA81725 should not give off any smell and should not be activating the brakes enough to cause smell if installed and adjusted properly. I've attached a video of this installation for you to reference. When installed correctly, this unit should be adjusted for sensivity. This conroller has a red LED indicator on front of unit that illuminates when trailer's brakes are applied. This
    view full answer...

  • How to Find the Brake Wire on a 2000 Chevrolet Express Van
  • In order to find the brake wire under your dash, you are going to need a circuit tester like part # 40376. Then you are going to need someone to engage the brake on your 2000 Chevrolet Express Van as you use your circuit tester to see which is the brake wire. When you find the right wire, a light will glow on the circuit tester. The wires you need to test are the bundle of wires coming out of the back of the brake pedal stop light switch. Use the circuit tester to find the hot wire only
    view full answer...

  • Troubleshooting Cruise Control Not Working After Brake Controller Install
  • Sounds like you connected the red (stoplight switch circuit) wire to the wrong circuit on your truck. When the cruise control on a vehicle starts acting up that is a tell-tale sign that the wrong circuit is being used for the red wire. What you want to do is use a circuit tester like part # PTW2993 to test the wires near the brake pedal to find the circuit that only sees 12 volts when the brakes are applied and none when the brakes are released. Correcting this should take care of both
    view full answer...

  • Red Light of Hayes Syncronizer Comes on When Applying Brakes with No Trailer Connected
  • Yes, the red light on the Hayes Syncronizer Trailer Brake Controller # HA81725 will come on whenever you apply your tow vehicle's brakes, even when no trailer is connected. However, no power is used when there isn't a trailer detected.
    view full answer...

  • What Functions do the Wires on the Hayes Syncronizer Trailer Brake Controller # HA81725 Connect to
  • Of course! The Hayes Syncronizer Trailer Brake Controller # HA81725 has 4 wires on it that connect to the following functions: Blue - Brake Signal Output Black - 12V Power from Battery White - Ground Red - COLD Side of Stop Light Switch (only gets hot when brake pedal is pressed) If you let me know what vehicle that you are installing it on I can check to see if there is a plug-in adapter so that you don't have to cut the connector off of your tow vehicle shuld one exist.
    view full answer...

  • Recommended Hayes Trailer Brake Controller Wiring Harness for 2003 GMC Sierra SLT with Tow Package
  • For your Hayes Syncronizer Trailer Brake Controller # HA81725 on your 2003 GMC pickup with tow package, you will want wiring adapter # HA81780-HBC. This will plug into your junction box beneath your vehicle's dash. That is all you will need as you stated.
    view full answer...

  • Why Does Hayes Syncronizer Brake Controller HA81725 Not Light Up When Pedal is Pressed
  • The display on the Hayes Syncronizer Trailer Brake Controller # HA81725 should illuminate both when you press the brake pedal and when you use the manual override lever. If it does not light up when you press the brake pedal then either there is a problem wit the red wire's connection to the brake light circuit or you have the power set so low that the display does not light up. The controller will apply full power with the manual lever but with the brake pedal it will illuminate only
    view full answer...

  • Hayes Brake Controller Install Harness Recommendation for 2014 Dodge Ram
  • To install a Hayes Syncronizer Brake Controller part # HA81725 in your 2014 Dodge Ram you would need the install harness part # HA81797-HBC which is a confirmed fit for your truck.
    view full answer...

  • Is it Normal for Brake Controller Light to Stay On When Not in Use
  • Brake controllers don't have an off switch and are designed to go into a sleep mode after 15 minutes or so of inactivity. It sounds like your controller is wired up correctly in your 2009 Chevy Silverado and the controller just hasn't gone to sleep yet. You wouldn't want to just unplug it as that will cause it to lose it's user settings.
    view full answer...

  • Uninstalling Hayes Syncronizer Brake Controller From 2014 Ford Explorer
  • To disconnect the Hayes brake controller you can simply unclip the wiring connection behind your trailer brake controller and tuck it out of the way. Then you can remove the brake controller from it's mount and either discard it or sell it. It will not in any way effect the braking on your vehicle. It only captures the brake light signal and then sends power to a trailer with brakes. Removing it will have no impact on your vehicle but only on your trailer towing ability.
    view full answer...

  • Red Light Not Illuminating On Hayes Syncronizer Trailer Brake Controller in 2002 Chevy Silverado
  • The red light of the Hayes Syncronizer Trailer Brake Controller part # HA81725 should only illuminate when the vehicle's brakes are depressed which activates the trailer brakes. If your not getting the red light when you depress the brake pedal it doesn't sound like the brake controller has power. It sounds like you are using the hayes brake controller adapter wire part # HA81781-HBC, you may want to check the fuses in the Chevy to make sure all of the factory tow package fuses are
    view full answer...

  • Brake Controller Install Harness for Hayes Synchronizer in a 2014 Chevy Silverado 1500
  • To install the Hayes Brake controller part # HA81725 in your 2014 Chevy Silverado 1500 only requires you to use the install harness part # HA81798-HBC which is a confirmed fit.
    view full answer...

  • Brake Controller Wiring Harness For A 2009 Dodge Ram 2500
  • The correct wiring harness that will connect the Hayes Syncronizer Trailer Brake Controller part # HA81725 to factory wiring harness on your 2009 Dodge Ram 2500 is the Custom Wiring Adapter for Hayes Brake Controllers part # HA81782-HBC. This a complete plug and play option that will not require hardwiring unless you do not already have a factory trailer connector installed, in that case you will need to use the hardwire wiring harness that comes with the Hayes Syncronizer Trailer Brake
    view full answer...

  • Will Hayes Sincronizer Trailer Brake Controller Fit on a Honda Goldwing Motorcycle
  • Yes, the Hayes Syncronizer Trailer Brake Controller # HA81725 is a good choice with your Honda Goldwing. A time delayed controller is a better choice on a motorcycle because of the limited space for installation. A proportional controller has more limitations as to how they can be mounted which will be an issue on a bike. Also, the leaning of a motorcycle while turning will tilt the controller and a proportional controller cannot function this way. To connect the controller to the
    view full answer...

  • Does Hayes Brake Controller Install Harness # HA81794-HBC Fit 2016 Ford F-150
  • Yes, the Hayes brake controller install harness part # HA81794-HBC that you referenced is a confirmed fit for your son's 2016 Ford F-150. The most popular brake controller used with this harness is the Hayes Genesis part # HA81790.
    view full answer...

  • Which Hayes Brake Controller Install Harness Fits 2015 Ford E-450 Cutaway Chassis
  • The correct Hayes brake controller install harness that fits your 2015 Ford E-450 cutaway chassis is the part # HA81788-HBC and not the one you referenced as that fits newer models.
    view full answer...

Info for these parts were:

Edited by:
Lindsey S
Expert Research:
Jameson C
Installed by:
Cole B
Written by:
Tammy D
Updated by:
Sarah W

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